Source: Unearthed Arcana 85 - Wonders of the Multiverse

You have absorbed primeval magic that gives you an echo of the might of giants. Choose one of the kinds of giants listed below. As a bonus action, you can call on the power of your giant magic to imbue your attacks with additional power. The next time you hit a target with a melee or thrown weapon attack within the next minute, the attack has an additional effect depending on the origin of your giant magic:

• Hill Giant. The target takes an extra 1d6 damage of the weapon’s type. If the target is a creature, it must succeed on a Strength saving throw or be knocked prone.
• Stone Giant. The target takes an extra 1d12 bludgeoning damage. If the target is a creature, it must succeed on a Strength saving throw or be pushed 10 feet away from you in a straight line.
• Frost Giant. The target takes an extra 1d8 cold damage. If the target is a creature, it must succeed on a Constitution saving throw, or its speed is reduced to 0 until the start of your next turn.
• Fire Giant. The target takes an extra 1d12 fire damage.
• Cloud Giant. The target takes an extra 1d6 thunder damage. If the target is a creature, it must succeed on a Wisdom saving throw, or you become invisible to it until the start of your next turn.
• Storm Giant. The target takes an extra 1d8 lightning damage. If the target is a creature, it must succeed on a Constitution saving throw, or it has disadvantage on attack rolls until the start of your next turn.

The saving throw DC for these effects equals 8 + your proficiency bonus + your Strength or Constitution modifier.

You can use this bonus action a number of times equal to your proficiency bonus, and you regain 2 expended uses on a short rest and all expended uses when you finish a long rest.